The first day of training camp this summer saw Javontee Herndon, the wide receiver who helped spark the Chargers' punt return game in 2015, field a welcome-back punt on a warm, morning practice.

He ran after the catch.

He cut on his left knee.

Pop.

The second day saw wide receiver Stevie Johnson, a route-running whiz whose technique is such that some teammates incorporate elements of it into their own, run a shallow route in a 7-on-7 period. He dove for a pass. He jumped to his feet. Then, he limped, hopped on one leg and fell back to the ground, clutching his right knee.

Another.

Injuries at Chargers Park had begun to add up.

Those first two practices were the start to a statistical anomaly, the franchise ruling a player out for the year after nine of its first 11 regular-season games in 2016. That does not include the earliest injuries in July and August.

It is obvious, the talent loss that comes with being the NFL’s most injured team. Overlooked is the cost.

Being this hurt is expensive.

The toll can sway front-office decisions.

In recent weeks, sources within the organization agreed to discuss on background the hidden impact of such personnel losses. None of this was done to apply for a hall pass for a 5-7 record entering Sunday in Carolina. Simply, this is an attempt to view the cumulative scope of an injury rash that, according to Man Games Lost, ranks worst in the league.

That title comes at a price.

All players on injured reserve count against a team’s salary cap. While their names disappear from a 53-man roster, they don’t on the books, the cap the only NFL field on which every player — healthy or injured, starter or sub — makes an impact.

Today in San Diego, 17 players are on injured reserve. Elsewhere in the division, Kansas City has nine, Oakland has six and Denver has five. The Chargers also have running back Dexter McCluster (forearm) on the Reserve/Non-Football Injury List. He financially counts as if he’s on IR, so it may as well be 18.

Michael Gehlken

(Michael Gehlken)

These 18 account for $29.3 million in total cap space and have earned $35.0 million in cash this year. Fourteen of the 18 were in uniform in four games or fewer this season. Wide receiver Keenan Allen suffered a non-contact anterior cruciate ligament tear in Week 1. His cap and cash cost are $7.7 million and $15.2 million, respectively, the priciest among the group.

The Chargers have not executed a contract extension since Allen’s four-year, $45 million deal on June 10. Why none for running back Danny Woodhead? Why none for outside linebacker Melvin Ingram or someone else?

The financial repercussions of injuries, one team official cited, are part of the reason.

Now, it’s not all-encompassing. A Woodhead extension, for example, theoretically could have been done prior to training camp, before injuries began to stack. The extension backlog also was linked to the unknown cash flow in rookie defensive end Joey Bosa’s contract. The team waited to see how much it’d devote there in terms of his signing bonus payout for this calendar year — in recent years, the Chargers routinely have ranked among the league leaders in cash spent on their roster, but they still carry a ceiling for such spending.

Signed on Aug. 29, the Bosa deal proved to require quicker cash flow than projected, by which point injuries piled up. The team was en route to blow past its undisclosed cash budget. Little did it know the degree to which the regular season would exacerbate that.

Herndon and Johnson? They were merely a prelude.

The Chargers placed Allen (knee) on injured reserve after the first game, Woodhead (knee) after the second, inside linebacker Manti Te’o (Achilles) after the third, cornerback Jason Verrett (knee) after the fourth, inside linebacker Nick Dzubnar (knee) after the fifth. …

Money allocated to those on injured reserve is not considered “dead money.” According to “Crunching Numbers,” a 2016 book that surveys NFL salary-cap practices and was written by Jason Fitzgerald and Vijay Natarajan, dead money is the “salary cap charge that remains on a team’s payroll even after the player is released or traded.”

These players are still here, and they carry hidden costs.

The Chargers must identify replacements on the 53-man roster, be it via free agency or the practice squad, for a player lost midseason. Team officials said that the financial implications from the injury deluge, at times, have dictated the experience level of free-agent replacements. A veteran with several accrued NFL seasons comes at a higher minimum salary charge. Cap issues influenced the team to target less experienced, lower-minimum players.

That is despite the Chargers’ planning efforts.

All 32 teams budget a certain amount of money into a “reserve,” or pool of funds they set aside entering a season in anticipation of injuries to come. The Chargers did that — they restructured quarterback Philip Rivers’ contract on Sept. 7 to pull it off, adding $4.5 million in 2016 cap space — but even then, they’ve dealt with cap issues.

At the time of that Rivers deal, the team had 14 players on injured reserve.

Five were later released on paid injury settlements.

In late July, the Chargers saw injuries add up during their first days of camp. In the coming months, those injuries added up, the cost constricting their roster flexibility and leaving them hugging the salary cap, a six-figure amount to spare now with four games to go.